In existing specimen tests, fluid reagents are required for chemical analyses, preparation of reagents, chemical syntheses, and reaction detection on the order of milliliters (ml) to microliters (μl). Tests performed using test-tubes or the like can now be performed on the order of nanoliters (nl) by formation of a fine flow passage (including a reaction field) using a litho-process and a thick film process technology. The micro total analysis system (μ-TAS) is a technology that utilizes such fine reaction fields. The μ-TAS technology is applicable to fields of genetic testing, chromosomal testing, cell testing and so forth used for medical tests and diagnoses, biotechnologies, tests of substances present in very small amounts in the environment, research on the cultivating environment for agricultural products and the like, genetic tests of agricultural products, and so forth. One example of use of a flow passage device, to which the μ-TAS technology is introduced, as a reaction field is the polymerase chain reaction (PCR).
In order to analyze a very small amount of nucleic acid such as deoxyribonucleic acid (DNA) or ribonucleic acid (RNA), the nucleic acid needs to be amplified to an amount at which the nucleic acid can be detected by fluorescence detection or other light detection. The PCR method has been used as a method of amplifying the nucleic acid.
PTL 1 discloses an optical analysis system as a system that uses the μ-TAS and performs the PCR as described above. The optical analysis system disclosed in PTL 1 includes a substrate including a microfluidic channel, a thermal generating unit operable to provide heat to and absorb heat from at least a portion of the microfluidic channel, and an image sensor disposed in relation to the substrate such that the portion of the channel is within the field of view of the image sensor.
One of the main problems to be solved in a flow passage device using a fine flow passage is to efficiently detect a light signal in the flow passage. In view of the above-described problem, PTL 2 discloses a technology in which inner surfaces of a flow passage are made to be reflective surfaces having high reflectivity by mirror finishing or another processing method so as to allow light emitted in the flow passage to be efficiently obtained.